Abstract [en]

AbstractScania trucks has had a rapid development in recent years, in electronics and automatic control engineering. A sensor which has not had the same trend is the ambient temperature sensor that was introduced in Scania trucks 1987. In total there are currently 10 different ECU systems that use the sensor signal. It has been shown that the ambient temperature sensor on Scania trucks have shown to high value in certain driving cases. Deviations have not been unusual when the engine is hot and the truck is running at speeds below 30 km/h or running at idle, for example at a red light. The problem has been shown to be greater at lower ambient temperatures. Measuring the correct temperature outside a truck is pretty difficult when the vehicle has many heat sources that may affect the result. This has led to systems that have a high dependence on good accuracy has been forced to spend resources on complex filtering systems to obtain a reasonably accurate temperature reading.In the future there are greater demands on the sensor signal when more and more systems require better accuracy to meet stricter emission, fuel economy and comfort requirements. The purpose of this report is to create an understanding of how well the current ambient temperature signal fit current and future needs and the potential of any developed various proposals for sensors and placement. There are also requests to find a placement of temperature sensor that can operate on all cab models to reduce the number of variations.Of all the locations that were tested, the position at the bottom of the rearview mirrors showed a good combination of reaction time and stability. This location would require less cabling than the present location and be rather tolerant for future cabin changes. The location is also recommending from a workshop point of view as the position is more accessible. The recommendation is to place the sensor in the bottom of the rearview mirror on the driver side.